In the era of Industry 4.0, 3D printing, or additive manufacturing (AM), has revolutionized product design and manufacturing across various sectors. This review explores the evolution of 3D printing technology and its impact on industrial innovation, highlighting advancements in aeronautics, the automotive industry, and biomedicine. Various AM processes, such as binder jetting, direct energy deposition, and powder bed fusion, and materials like metals, polymers, ceramics, and composites, are discussed. Innovations like high-speed sintering, continuous liquid interface production, and bioprinting demonstrate ongoing advancements. The potential of 3D printing in personalized medical applications is emphasized due to its flexibility in geometry and materials. Despite progress, challenges like standardization, material quality, recycling, sustainability, and economic feasibility hinder widespread adoption. Overcoming these challenges is crucial for optimizing 3D printing technologies, ensuring high-quality, efficient, and affordable production. The review also addresses the future prospects of 4D and 5D printing technologies and their potential applications in various industries. This overview underscores 3D printing’s role in shaping the future of manufacturing within the context of Industry 5.0, emphasizing human–machine collaboration and sustainability.

Polyether urethane (PU)-based magnetic composite materials, containing different types and concentrations of iron oxide nanostructures (Fe₂O₃ and Fe₃O₄), were prepared and investigated as a novel composite platform that could be explored in different applications, especially for the improvement of the image quality of MRI investigations. Firstly, the PU structure was synthetized by means of a polyaddition reaction and then hematite (Fe₂O₃) and magnetite (Fe₃O₄) nanoparticles were added to the PU matrices to prepare magnetic nanocomposites. The type and amount of iron oxide nanoparticles influenced its structural, morphological, mechanical, dielectric, and magnetic properties. Thus, the morphology and wettability of the PU nanocomposites surfaces presented different behaviours depending on the amount of the iron oxide nanoparticles embedded in the matrices. Mechanical, dielectric, and magnetic properties were enhanced in the composites’ samples when compared with pristine PU matrix. In addition, the investigation of in vitro cytocompatibility of prepared PU nanocomposites showed that these samples are good candidates for biomedical applications, with cell viability levels in the range of 80–90%. Considering all the investigations, we can conclude that the addition of magnetic particles introduced additional properties to the composite, which could significantly expand the functionality of the materials developed in this work.

This review explores the integration of polymer materials into piezoelectric composite structures, focusing on their application in sensor technologies, and wearable electronics. Piezoelectric composites combining ceramic phases like BaTiO₃, KNN, or PZT with polymers such as PVDF exhibit significant potential due to their enhanced flexibility, processability, and electrical performance. The synergy between the high piezoelectric sensitivity of ceramics and the mechanical flexibility of polymers enables the development of advanced materials for biomedical devices, energy conversion, and smart infrastructure applications. This review discusses the evolution of lead-free ceramics, the challenges in improving polymer–ceramic interfaces, and innovations like 3D printing and surface functionalization, which enhance charge transfer and material durability. It also covers the effects of radiation on these materials, particularly in nuclear applications, and strategies to enhance radiation resistance. The review concludes that polymer materials play a critical role in advancing piezoelectric composite technologies by addressing environmental and functional challenges, paving the way for future innovations.

In this work, improved fracture toughness of tetra-functional epoxy polymer was obtained using two-dimensional (2H polytype) molybdenum disulfide (MoS₂) nano-platelets as a filler. Simultaneous in-situ exfoliation and functionalization of MoS₂ were achieved in the presence of cetyltrimethylammonium bromide (CTAB) via sonication. The aim was to improve the dispersion of MoS₂ nanoplatelets in epoxy and enhance the interfacial interaction between nanoplatelets and epoxy matrix. Epoxy nanocomposites with CTAB functionalized MoS₂ (f-MoS₂) nanoplatelets, ranging in content from 0.1 wt% up to 1 wt%, were fabricated. Modified MoS₂ improved the fracture properties (81%) of tetrafunctional epoxy nanocomposites. The flexural strength and compressive strength improved by 64% and 47%, respectively, with 0.25 wt% loading of f-MoS₂ nanoplatelets compared to neat epoxy. The addition of f-MoS₂ nanoplatelets enhanced the thermomechanical properties of epoxy. This work demonstrated the potential of organically modified MoS₂ nanoplatelets for improving the fracture and thermal behavior of tetrafunctional epoxy nanocomposites.

Fourier-transform infrared (FTIR) spectroscopy has been extensively used in plastic pollution research, since it has the advantages of great simplicity, rapidity, and low cost, being widely employed in the fingerprint identification of molecular composition and structure. The present study evaluates attenuated total reflection (ATR)–FTIR spectroscopy as a sensitive and effective assay for the identification of deoxyribonucleic acid (DNA) isolated from experimental animals. Various composite materials based on recycled polyethylene terephthalate (PET) as the main component, along with high-density polyethylene (HDPE), polypropylene (PP), and aluminum nanopowder obtained using an injection-molding machine, were used as substrate contaminants. The contamination was performed using quantified nucleic acid solution added in droplets to the clean, decontaminated samples, which were then dried and kept in a protective environment until the analysis. ATR–FTIR (with an FTIR spectrometer equipped with an ATR accessory) spectroscopy was used to analyze the bare composite materials’ substrates and the DNA-contaminated samples. To the best of our knowledge, the evaluation of PET packaging contamination with DNA species by FTIR has not been reported previously. This study demonstrated that FTIR spectroscopy could provide a rapid, sensitive, and reliable approach for screening of biochemical contaminants on composite materials based on recycled PET.

The European methodology for plastics, as a feature of the EU’s circular economy activity plan, ought to support the decrease in plastic waste. The improvement of recycled plastics’ economics and quality is one important part of this action plan. Additionally, achieving the requirement that all plastic packaging sold in the EU by 2030 be recyclable or reusable is an important objective. This means that food packaging materials should be recycled in a closed loop at the end. One of the most significant engineering polymers is polyethylene terephthalate (PET), which is widely used. Due to its numerous crucial qualities, it has a wide variety of applications, from packaging to fibers. The thermoplastic polyolefin, primarily polyethylene and polypropylene (PP), is a popular choice utilized globally in a wide range of applications. In the first phase of the current experiment, the materials were obtained by hot pressing with the press machine. The reinforcer is made of Al nanopowder 800 nm and Fe nanopowder 790 nm and the quality of the recycled polymer was examined using Fourier transform infrared spectroscopy (FTIR), a scanning electron microscope (SEM), and differential scanning calorimetry (DSC). From DSC variation curves as a function of temperature, the values from the transformation processes (glass transition, crystallization, and melting) are obtained. SEM measurements revealed that the polymer composites with Al have smooth spherical particles while the ones with Fe have bigger rough spherical particles.